What is a complex system?

I recently became a member of the Transformational Systems Engineering Working Group on Complex Systems of INCOSE (International Council on Systems Engineering).

Delving into this has been a fascinating experience, and definitely beyond my usual area.   The first question that the group is grappling with is “what makes a system complex, rather than complicated”

While there does not seem to be a single firm answer,  the key difference seems to revolve around the interdependence and interaction of the component systems.  Are the interactions predictable?  Is the state of the components known?

As we delve more into this, I will be posting additional entries.  For a quick overview on the need for transformational SE  – Check out this presentation on the limits of systems engineering.